last time i bleed during intercourse i was pregnant with my son

Started bleeding during sex, last time i bleed during sex i was pregnant with my son. I went to doctors to get pregnancy test got blood work done. Dr said considering my previous pregnancy and what had been going on she thinks its possible. She told me to atop takin birth control till i got my results back. Soi stopped. I also didnt take it that morning going to the doctors in case ahe told me to stop taking it (which she did). Later that might my boyfriend and i had unportected sex. Omce that night. And the mext morning. I went to get my results the next day and it was negative. I think i may have gotten pregnant from unportected sex while not taking my birth control. i took them immideitly after i found out i was not pregnant and the next day i had light spotting. Followed by brown discharge during sex, and now i am lighty bleeding again. The spotting was very on and off.. just wondering if i may be pregnant? What you think the % of me being pregnant could be? The boyfriend and i have been together for just over 3 years. We have a 2 yr old son together too and dont mind having another kid:) let me know